A semiconductor light-emitting device described in International Publication No. WO 2014/136962 (Patent Document 1) includes an active layer, a pair of cladding layers sandwiching the active layer, and a phase modulation layer optically coupled to the active layer. The phase modulation layer includes a basic layer and a plurality of modified refractive index regions each having a refractive index different from the refractive index of the basic layer. In a case where a square lattice is set on the phase modulation layer, each of modified refractive index regions (main holes) is arranged so as to match the center point (lattice point) of the corresponding region (having a square shape) in the square lattice. An auxiliary modified refractive index region (auxiliary hole) is provided around the modified refractive index region, enabling light having a predetermined beam pattern to be emitted.